What Is Case Fill Rate and How Is It Calculated?

Case Fill Rate The percentage of ordered cases that are fulfilled from available inventory as requested. This metric measures the share of customer case quantity requested on an order that ships from stock without backorders, substitutions, or manual corrections.

Case fill rate is a core fulfillment KPI used at the distribution center and enterprise level. It answers a specific operational question: of the cases customers asked for on an invoice or purchase order, how many were delivered from available inventory exactly as requested? The result is typically expressed as a percentage and used alongside related metrics — unit fill rate, line fill rate, and on-time delivery — to paint a fuller picture of service performance.

How The Metric Is Calculated

Calculation is straightforward when source systems are aligned. Use the formula:

Case Fill Rate (%) = (Total Cases Fulfilled As Requested / Total Cases Ordered) × 100

Key operational decisions determine what counts as "fulfilled as requested." Typical choices include whether to count partial shipments, permitted substitutions, and canceled lines. For consistency, define these rules in your KPI definitions so comparisons over time or between sites remain valid.

Common Data Sources

• WMS Records: Pick and ship confirmations provide authoritative counts of cases picked and shipped by case ID or SKU.
• OMS/ERP Orders: The original order quantities (cases ordered) come from order management or ERP systems and must be matched to pick records.
• Advanced Shipping Notices (ASNs): Carrier or freight records confirm what actually left the dock and help reconcile exceptions.

Why It Matters

High case fill rates reduce customer complaints, fewer expedited shipments, and lower costs associated with backorders and customer service interventions. For retailers and grocers that sell by the case, a high case fill rate directly preserves sales and margin. For B2B customers placing large-case orders, reliability in case quantities is a key contractual requirement.

How It Varies By Business Model

Expect different benchmarks depending on product and channel. Grocery, beverage, and palletized fast-moving SKUs usually target very high case fill rates (98–100%) because downstream retailers require full-case deliveries. E‑commerce models selling mixed-case assortments may accept lower case fill but compensate with high unit or line fill rates.

Practical Example

Over a month a DC receives 10,000 cases ordered across multiple purchase orders. The WMS and shipping system show 9,600 cases shipped exactly as ordered; 200 cases were partially shipped and 200 cases were backordered. The Case Fill Rate = (9,600 / 10,000) × 100 = 96%.

Tips To Ensure Accurate Calculation

• Label: Reconcile by order number and SKU to avoid double counting cases across split shipments.
• Label: Decide how to treat substitutions and document the policy in SLA/KPI definitions.
• Label: Use the ship confirmation (scan-based) as the authoritative record, not pick lists that can be adjusted later.

Who Uses The Metric

Warehouse managers, operations leaders, sales and account managers, and supply planners all use case fill rate. Operations teams act on shortfalls; sales teams incorporate performance into customer reviews; planners use trends to adjust safety stock and replenishment rules.

In short, the Case Fill Rate quantifies how well inventory and fulfillment processes deliver ordered cases without exception. Accurate collection, clear counting rules, and alignment between WMS and order systems are essential to producing a reliable percentage you can act on.